简介:Thecorrosionofrefractoriesresultsfromreactivetransport,namely,transportofagentsandchemicalreactionsoftheseagentswithimpregnatedmedium.Ononehand,thetransportinvolveseitherdiffusionorimpregnationdependingonthestateofthecorrosiveagentsandthemicrostructureofthehostmedia.Ontheotherhand,chemicalreactionsmaybeverynumerousandcomplex.ThisstudyfocusedonthereactiveimpregnationofAl2O3-CaOslagintoporoushighaluminarefractory.Thetransportpropertiesoftherefractorymaterialwereidentifiedbymeansofadedicatedcapillaryrisingtest.ChemicalreactionsbetweenthesolidhighaluminaskeletonandAl2O3-CaOslaginvolvesuccessivedissolution/precipitationmechanismsformingaluminatesoflime.Contrarytothethermodynamicpropertiesofthebinarysystem,thekineticsofthesesolid/liquidreactionsisnotwellknown.Corrosiontestsassociatedwiththequenchingmethod,XRDanalyseswereperformedforabetterunderstandingofthekinetics.Theresultsofthisstudyopenupacouplingapproachforpredictingthecorrosionwearofrefractory.
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简介:Thedevelopmentofefficientbondingagentsisoneaspectoftheadvancementofrefractories.Basedonanewlydevelopedbindersystem,anewgenerationoftar-resinbondedmagnesiacarbonproductswithhighperformancehasbeendeveloped.Furthermore,thebindersystemcharacterizedbyhighcarbonyieldaftercarbonizationresultsinforminganextremelystrongcarbonbonding.Itcanimproverefractoriespropertiestogetnewproductwithmoreadvantagesthanoldrefractories:moreeconomic,lowercostandlowtoxicity.Tar-resinisnotonlyusedinshapedrefractories,butalsoinmorerefractoriestypes,suchasmonolithicrefractories.ImmersionexperimentsofMgO-Cmonolithicrefractoriessamplesinliquidsteelat1600℃havebeencarriedoutforsteelmakingindustry.TheseexperimentsshowedtheformationofadenseandcontinuousMgOrichlayer,ontheinterfacebetweenrefractoryandsteel,andthepossibleformationofinclusionsaslargeclustersprotrudingfromtherefractorysurface.Forthemechanicalproperties,thepowderwasheatedupto1400℃inairtoremovecarbon,andwassubsequentlyformedintobrickshape.StandardASTMwasusedtodeterminetheMOR,porosityanddensity.Itisfoundthatantioxidantmaterialsplayanimportantroleinimprovingthemechanicalproperties.
简介:ThisworkstudiedthecharacteristicsofSiO2distributionandstructureofsilicatephasesinMgO-ZrO2compositessynthesizedbyrawmaterialsoflightfiredmagnesitendzircon,Theresultsindicatethat30wt%-40wt%SiO2contentinthesystemisexistedintheformofcrystallineofforsterite(M2S),theremainderingofSiOcontent(60wt%0-70wt%)isexistedintheglassphase,Thechemicalcompositionofglassphaseiswellagreedwiththechemicalcompositionofmonticellite(CMS).
简介:MobarakehsteelCompanyproduces3milliontonsofsteelannuallywitheight180tonsEBTfurnaces.Differenttypesofmagnesia-carbonrefractorieshavebeenemployedatslaglineduringlast5years.InthepresentstudythewearandcorrosionofMgO-Crefractoriesofthesefurnaceshavebeenstudiedviapost-mortemanalysisofusedbricksandtheobservationofoperationaleffects.Laboratorycorrosiontestswerealsoarrangedtoinvestigatetheeffectofslagchemistryandthemechanismofchemicalcorrosion.Characterizationofdifferentmagnesia-carbonbricksclarifiedthatthecrystalsize,typeandchemistryofmagnesiaaswellasgraphitestructurehavethemaininfluenceoncorrosionresistance.TheCaO:SiO2ratioinslagalsoplaysavitalroleinthewearofslaglinerefractories.Theironoxidecontentofslagalsohasamajorroleingraphiteoxidation.Ofmetallurgicalparameters,theelectricpowerinputandthecontacttimehavegreatinfluenceonrefractorieslife.TheresultswillbediscussedwithemphasisonparticularoperationalfactorsinMobarakehsteelplant.
简介:TheeffectoftheadmixturesofAlandSimetalsandB4CandMgAlONcompoundsontheoxidationofMgO/Si3N4compositerefractoryhasbeenstudied,whichisapromisingcarbonfreerefractoryforsteel-makingapplicatlon.Thefourkindsofadmixturescanbeusedasanti-oxidantsforSi3N4,butthemixtureofAlandSiachievedthebestresult.Themixturecannotonlyplaytheroleasantioxidant,butalsoassistthesinteringprocessandhelpformdensesinteringlayer,improvingthepropertyofthecomposite.